Burglar-alarm



(Model.)

.Patented April 12,1881..

UNITED STATES .PATENT OFFICE.

HENRY HOLGROFT, OF MEDIA, PENNSYLVANIA.

BURGLAR-ALARM.

SPECIFICATION forming part of Letters Patent No. 240,024, dated April 12, 1881. Application filed October 6, 1880. (Model.)

To all whom it may concern: n

Beit known that I, HENRY HoLoRoFT, of Media, Delaware county, and State of Penu- Sylvania, have invented a new and useful Improvement in Burglar-Alarms, of which the following is a specitication.

My invention relates to alarms which may be attached to doors, windows, or other places where ala-rms may be desired in case of an attempted theft, burglary, or intrusion; and it eonsistsjn the combination and arrangement of a metal frame provided with an arm, in the end of which is a small circular recess for holding one or more paper torpedoes, a spindle to which is connected an arm having at its extreme end a hammer, which is operated by a pin, retaining-catch, and coiled spring, as will bc hereinafter described, referring to the an. nexed drawings, making a part of this speciiication, in which- Figure l is 'a view of my improved alarm suspended on a door-knob ready for action. Fig. V2 is a view ofthe same after having been cast oi' the knob and giving thealarm. Fig. 3 is a viewof the alarm detached from the suspending-cord. The other views are separated and detached parts of the alarm, and indicated by letters of reference.

Similar letters refer to similar parts throughout the several views.

The main part of the machine is represented by the arm A, hub G, and spindle J, which should be made ot' metal.V Cast-iron will do. In the arm A is recessed a small recess, d, about one-eighth of an inch deep, and of diameter a littleless than the paper torpedoes to be used. In the hub G is drilled a hole for the free working ot' the spindle S. At the top of i the hub Gis a notch, R. VOn the spindle J is placed a coiled spring. One end is fastened to spindle J, and the free end rests on the arm a. The spindle S isprovided with an eye, to

which is attached the cord D. In this spindle is also a small pin, b, and on the arm a is the hammer C. These parts may be made of cast- 4 5 iron, with the exception of the spring B, which should be of steel or brass spring-wire.

.The manner of using my improved alarm is as follows: The pin bis turned and pressed into the catch R and held by friction, which ele- 5o vates the hammer C, as shown in Fig. l. One or more paper torpedoes (such as used by children in toy pistols) are pressed by the linger in the recess d. The free end of the cord D:i-v looped around the knobshank, and the hook 55 E is hung on the knob F, thussuspending the alarm, as shown in Fig. 1. If the knob F be, turned from the outside of the door the hook E will be thrown oft' the knob, and as the alarm falls it will draw tight the slack-cord, 6o n release the pin b from the catch R, and the coiled spring B will force the hammer O against the torpedoes placed in the recess d, explode them, and give the alarm.

Itis obvious that'my invention may be sus- 65 pended on any suitable support, and the hook E connected by a string to a window-sash, shutter, or other object, so thatit may be thrown off by moving such object and give the alarm, the same as above described. 7o

I am aware that it is not new to suspend the alarm on a door-knob, nor to make an alarm by exploding torpedoes. These I do not claim 5 but l claim as my iuvention- The combination and arrangement of hook E, suspending-cord D, spindle S, pin b, catch R, coiled spring B, arm a, hammer G, and recess d, as shown, described, and for t-he purpose specified.

H. HOLGROFT. Witnesses:

J oHN SHINN, `JOHN S. G01N. 

